Answer:
192.08J
19.6m/s
Explanation:
Since there will be no potential energy when the ball is on the ground, the change in potential energy is equal to the potential energy at the start when the ball is 19.6m above the ground.
PE=mgh
=(1)(9.8)(19.6)
=192.08J
v²=u²+2as, where v is the final velocity, u is initial velocity, a is acceleration and s is distance. Initial velocity is 0 since it starts at rest.
v²=u²+2as
v²=0²+2(9.8)(19.6)
v=√384.16
=19.6m/s
Answer:

Explanation:
From the question we are told that:
Force P=88Ib
Mass of crate M_c=210Ib
Generally the equation for Frictional force F is mathematically given by


with 

Therefore since Static Friction supersedes applied force body remains at rest.
Frictional force =88Ib (negative)

Answer:
A. The forces are the same size and in opposite directions.
Explanation:
Just as an opposite number will cancel a number: -1 +1 = 0, so an opposite force will cancel a force, with the result that the net is zero.